Discussion in 'Photo & Video Gallery' started by carl, Nov 14, 2008.
We hit 20psi earlier in the day so I don't think so.
rally rally rally
i want a ride in it with that much torque.
In theory, at higher airflow rates the restrictor will cause lower pressure on the inducer side of the compressor, thus limiting the absolute pressure the compressor can make.
i was down there w him yesterday, there were a few boost leaks throughout the tune session. all the lines/hoses that hold PSI will be getting gone through and re-clamped at least once, maybe three times. and then see if it holds better.
why would you do the work 3 times?! It's not a timing belt :laugh:
or an engine install?
btw, what's on the turbo inlet? Aluminum tape?
probably that heat wrap
used Twice Bake Potato trays?
jb weld, consensus was it would hold psi better the AL tape
in other words, Carl ran out of aluminum tape because he uses it on EVERYTHING.
Just a curious thought...
Have you thought about running with a block off plate instead of using your bov? I spoke with some guy a while back who builds rally cars (the guy who built that brick vinyl wrapped rs) and noticed he didn't have a bov on the swapped rs we were lookin at. He said it's to keep the boost up. I know this would be harder on the turbo, but have you ever thought about it?
you talked to matt zawada - Bob's car was far more prepped than ours and it appeared their budget was much greater than ours. it's not worth it for us. any benefits are far outweighed by the downsides in our situation (not a lot of money). if someone brought me a vf39 in very good condition to put on before each race maybe, otherwise it's not worth the increase in chance of losing a turbo on stage.
haha just thought I'd ask. I wasn't sure how "hardcore" you were lol. I'd like to drive in a car w/o a bov. I'd be curious to know how it drove.
i do belive it should be like driving a car with a roots type supercharger. With out a bov u will have some boost all the time and no turbo lag(or not as much turbolag). superchager u have boost all the time under acceleration.
But i could be wrong. never drove a car with out a bov before.
Its not that big of a difference for a street car. I ran one of my turbo setups w/o a BOV since I did not have the fittings to install the BOV I had.
I would wager that the amount you would gain would be hardly noticeable since if you are winding out gears, when you shift you will be right back into peak boost territory and the turbo will spool up lightning fast anyway. You gain a couple HPs quicker and get to hear a cool sound come from the Turbo (see Topgear testing the P2 to hear the sound) but you will burn through turbos much faster due to added wear.
I would just go anti-lag to keep your boost between gears. you will still eat turbos, but at least you get tons of boost on launch, and shoot fire. Or the other option is to run an automatic transmission. you dont have to let off to shift gears in the auto so you dont loose any boost.
Or an oil cooler.:biggrin:
Even better option: Get the ECU patch for Flat-foot shifting and launch control. Then you'll lose nothing.
Additionally - I don't see why you're so paranoid about running w/o a BOV. (NOT that you'd want to--a properly tuned one will work perfectly) Many turbo cars for many years were run without them. I had a friend with an 86 Shelby Charger. No diverter valve or BOV or bypass valve --whatever you wanna call it. There were 136,000+ miles on it, original turbo.
Running without a BOV isn't going to hold more boost since the compressor wheel will grind to a halt as soon as the throttle is lifted. That bark you hear is case in point.
A properly working and adjusted BOV will keep the rotating assembly moving in positive direction, and your recovery will be quicker. I noticed it with my GT2871. Upshifts at 4500 rpm with a properly working valve would zing up quicker than with a crappy slow reacting valve.
With my new setup, I will be getting the lightest possible spring available.
As far as coolers go, look into Laminova. Extremely compact water to oil coolers that you can put anywhere. I want one myself. Little hint.... they came on cop cars.
the cooler thing is a running joke (ask dave about it for teh LOL) - we don't really need one. At least not yet
EA82t subarus didn't have one either. But that was a low pressure system (6psi, IIRC). I suspect the same is true for the shelby charger. I wouldn't want to run more than about 8-10 without some way of releasing that pressure.
and Dan (Pidde) is exactly right, if you don't release that pressure, it drastically slows the compressor wheel. so yea, maybe your intake charge is a bit more pressurized when you first open the throttle plate, but it's still going to take longer to re-spin up the impeller.
The key lies within the application. There is a reason I put my BOV as close as possible to the TB, and have the shortest possible source line. Even cutting 15 in out of my source line on the old setup played significant dividends.
Response is key, and placement can give you a little buffer. The longer space between your turbo and valve gives a little buffer, but improper source plumbing negates that buffer.
Huh...cool. I think I learn something every time I read one of your posts or talk to you.
Just trying to share some education with experience. Experience has cost a lot, unfortunately.
I may actually try to change my BOV to a 45 degree angle with the piping. Same principle as a wastegate.
well this isn't really work on the car but it is rally related. Over the weekend a tire rack for the service truck was constructed. A huge thanks to Matt (mlgez) for letting me use his awesome garage since I can't fit the truck into mine lol). Also thanks to Matt's friend Bob and Tall Dan for assisting in the construction
me plasma cutting off a piece of 1/4" plate for the base
Matt welding a tube onto a baseplate
The overall frame clamped together to get welded
The baseplates are 12"x6"x1/4" steel plates. They have studs welded to them and drop through the truck's bed rails. 8"x2"x1/4" backing plates go on the other side. There is a 1.25"x1.25"x6" post welded to the plates that the frame drops onto (so it can be removed easily).
there are 2 rows for wheels, each row can hold 6. The tires sit in between two parallel bars. A tube is inserted down the hubs of the wheels and locks between the tall uprights pictured
It is more than strong enough to hold 12 wheels and gives us a good option to add sideboxes to it later for even more storage - not bad for $150 worth of metal and a weekend's work! I might add some gussets later just to make it a little more rigid.
and an sti wing for downforce
LOL, that was discussed at some point last night. Looks good finished Carl. I had a good time working on it last night. Wish I could have helped today too but company for an early Christmas. Glad everything worked out and the shop was adequate.
Awesome tire rack! I like the design, very functional and simple. You gotta post pics of it all loaded up now.
carl, we need a piece of this
to stand on top between the 2 different storage areas
thats what i came up with following you home
no, we need this
Looks good. I want to see it full of tires though....
too much work lol. I did a quick and dirty FEA on it to see if I was in the ballpark for holding 12 wheels/tires and it appears to be more than adequate
What was your Factor of Safety? And what directions did you test it?
I taught myself Mechanica in like 3 hours so it really wasn't very detailed. If I had ANSYS or Cosmos I would have done more than a static loading.
Lol, fair enough. The fact that you did it means its probably overbuilt.
rally car is looking good. Hope to see you guys out racing in 2010
you have any new vids or a new dyno chart since you got it turboed?
dont worry guys, i stood on top of it and shook about, then carl hung awkwardly on the side. its good to go
These testing conditions sound very similar to a real world scenario. I will now dub this the ZipTie Rally Jungle Gym.
i did see that chart, but i was wondering if you made any more changes since then cause you sai dyou were having trouble holding boost.